ODSSEY-SCD_Identification Of Markers to preDict the rISk of Sudden Cardiac Death in Moderated LVEF in ischEmic cardiomyopathY

Although advances in treatment and patient management have considerably improved post-infarction prognosis, the risk of sudden cardiac death remains a major concern. Sudden cardiac death (SCD) is defined as an unexpected death occurring within one hour of the onset of symptoms, often of arrhythmic origin. In patients who have survived a myocardial infarction, sudden death represents a persistent threat. This risk is often associated with complications such as left ventricular dysfunction, malignant ventricular arrhythmias, and structural alterations of the myocardium, all of which can favor the development of fatal cardiac events. Among the risk factors identified, reduced left ventricular ejection fraction, a history of ventricular arrhythmias and the presence of extensive scarring of the myocardium are particularly significant. Assessing the risk of SCD in post-infarction patients is crucial to determining appropriate prevention strategies, such as implanting automatic implantable defibrillators (ICDs). Assessment tools are varied, but currently only left ventricular ejection fraction (LVEF) \< 35% is identified and validated. However, this risk stratification is unsatisfactory, particularly in view of SCD in patients with a history of myocardial infarction and a moderately impaired LVEF (between 35 and 50%). Although the initial treatment of myocardial infarction is essential for the patient's immediate survival, managing the risk of sudden death in the long term remains a major clinical challenge. A multiparametric approach is needed to optimize prognosis and prevent premature death in these patients.

Inclusion Criteria: * Patients over 18 years of age * Hospitalized for acute STEMI within 6 months (Type 1 myocardial infarction according to ESC recommendations, Thygesen EHJ 2018). * Left ventricular ejection fraction between 35% and 50% at least 40 days after acute myocardial infarction (see above). * Under optimal tolerated medical treatment. * Covered by a social security scheme. * Legally competent to give voluntary informed consent to participate in the study. * Patient who will not participate in further studies involving an investigational drug or device until the end of the trial (i.e. 60 months). Participation in registries is authorized Exclusion Criteria: * Presence of a secondary prevention indication for implantation of an implantable automatic defibrillator (ICD) * Presence of a pacemaker * Administration of ventricular antiarrhythmic drugs other than beta-blockers (i.e. amiodarone, sotalol, flecainide) * Patients with systemic diseases (cancer, liver failure or end-stage renal disease) * Patients with assessed life expectancy \< 1 year. * Age \> 80 * Adult patient under legal protection (guardianship, curatorship or other legal protection measure) * The subject is pregnant or nursing or positive beta HCG for women of childbearing age * Patient participating in another clinical research protocol involving an investigational drug or device within the last 30 days (participation in a registry is permitted at the same time).